Which hormone is primarily associated with the regulation of blood volume and pressure?

The hormone primarily associated with the regulation of blood volume and pressure is angiotensin. Angiotensin is part of a complex pathway known as the renin-angiotensin-aldosterone system (RAAS), which plays a critical role in controlling blood pressure and fluid balance in the body.

When blood pressure drops or there is a decrease in blood volume, the kidneys release renin. Renin converts a plasma protein called angiotensinogen into angiotensin I. Angiotensin I is then converted to angiotensin II, primarily in the lungs, by the action of an enzyme called angiotensin-converting enzyme (ACE). Angiotensin II has several effects: it causes blood vessels to constrict, which increases blood pressure, and stimulates the release of aldosterone from the adrenal glands, leading to increased sodium and water reabsorption in the kidneys. This reabsorption helps to increase blood volume and pressure.

In contrast, adrenaline primarily prepares the body for fight-or-flight responses, cortisol plays a role in metabolism and stress responses, and insulin is crucial for glucose metabolism and regulating blood sugar levels. Therefore, angiotensin is directly linked to the mechanisms that regulate blood volume and pressure, highlighting its importance in cardiovascular health.